The state’s highest court has upheld the murder conviction of Michael T. Burnham, who beat a Brockton toddler in 1985 and was finally convicted in 2005 after investigators developed new evidence in the case.

Maureen Boyle

Michael T. Burnham was free for 20 years before a jury convicted him three years ago of killing a toddler in a Brockton apartment.

Now, he’ll stay behind bars for the rest of his life after the state Supreme Judicial Court upheld his first-degree murder conviction Tuesday.

“Justice may be finally done for this little girl, Rachelle,” Plymouth County District Attorney Timothy J. Cruz said.

Burnham had sought to win a new trial or get his first-degree murder conviction reduced to a lesser charge, where he would be eligible for parole.

He claimed to the court that his conversation with an ex-wife about the death shouldn’t have been allowed as evidence and the jury should have at least been able to consider manslaughter as a option in convicting him.

The court disagreed.

“We have reviewed the entire record, the transcript and the briefs, and decline to reduce the degree of guilt or order a new trial,” the SJC ruling noted.

Burnham, of Holbrook, was convicted of first-degree murder in 2005 in the beating and stomping death of his then-girlfriend’s daughter, 21-month-old Rachelle Pelletier, in a Brockton apartment in 1985.

The child’s mother, Margaret Earle of Weymouth, had been convicted earlier of second-degree murder after prosecutors convinced a jury she had failed to get the child help after the attack.

The case was one of a number of so-called “cold cases” prosecuted by the Plymouth County district attorney’s office in recent years and one of the first prosecuted when Cruz took office.

“We looked at every unsolved homicide here in the county of Plymouth then, and we have been continuing to do that,” Cruz said.

“People that choose to do this, to hurt children, to hurt the weak, we’ll get them,” he said. “It may not be today, it may not be tomorrow, but I’m always confident we will get them.”

In the case of Burnham and his ex-girlfriend, authorities had been eyeing the pair as suspects early on.

But it wasn’t until 2002, after investigators developed additional information to convince a grand jury to indict the pair, that they were charged. The information included a purported confession by Burnham to his now ex-wife in 1995.

It was that confession that Burnham tried to convince the SJC was inadmissible and shouldn’t have been used in his trial.

Burnham was convicted of killing Rachelle in a fit of rage. Authorities and witnesses testified he was upset that Earle was with friends and he was watching the toddler.

Earle was convicted of second-degree murder based on the theory that she knew of the abuse, covered it up for years, and did not take Rachelle to the hospital for treatment, letting the child die an agonizing death.